Hydrothermal synthesis of PbTiO₃ films

Well-crystallized polycrystalline films of tetragonal PbTiO₃ have been synthesized on Ti metal substrates in concentrated alkaline solutions of Pb(OH)₂ containing KOH by the hydrothermal method under saturated vapor pressure (2.0 MPa) at 200 °C. The film microstructure depended strongly on the Pb(OH)₂ and KOH concentration. The grain size became larger from approximately 0.6 to 6 μm with an increase of KOH concentration from 1 to 4 M at 0.07 M Pb(OH)₂, whereas the grains decreased in size with an increase of Pb(OH)₂ concentration at 1 M KOH concentration. PbTiO₃ film prepared in the aqueous solution of 0.07 M Pb(OH)₂ containing 2 M KOH showed a relative dielectric constant of about 215 and loss of about 5% at 1 kHz.